U.S. patent application number 13/499632 was filed with the patent office on 2012-09-27 for electronic, especially optical or optoelectronic component, and method for the production thereof.
This patent application is currently assigned to OSRAM Opto Semiconductors GmbH. Invention is credited to Klaus Hoehn.
Application Number | 20120241694 13/499632 |
Document ID | / |
Family ID | 43662662 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120241694 |
Kind Code |
A1 |
Hoehn; Klaus |
September 27, 2012 |
Electronic, Especially Optical or Optoelectronic Component, and
Method for the Production Thereof
Abstract
Electronic, in particular optical or optoelectronic, component
comprising a device which comprises a thermoplastic material which
has particles which comprise a core and a shell, wherein the shell
is disposed on the surface of the core and wherein the core
comprises aluminium.
Inventors: |
Hoehn; Klaus; (Forchheim,
DE) |
Assignee: |
OSRAM Opto Semiconductors
GmbH
Regensburg
DE
|
Family ID: |
43662662 |
Appl. No.: |
13/499632 |
Filed: |
September 20, 2010 |
PCT Filed: |
September 20, 2010 |
PCT NO: |
PCT/EP2010/063813 |
371 Date: |
May 30, 2012 |
Current U.S.
Class: |
252/512 ;
977/773; 977/810; 977/932 |
Current CPC
Class: |
H01L 33/60 20130101;
H01L 2924/0002 20130101; H01L 2924/0002 20130101; H01L 33/48
20130101; H01L 2924/00 20130101; H01L 33/641 20130101 |
Class at
Publication: |
252/512 ;
977/773; 977/932; 977/810 |
International
Class: |
H01B 1/22 20060101
H01B001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2009 |
DE |
102009047877.9 |
Nov 25, 2009 |
DE |
102009055765.2 |
Claims
1. An electronic, in particular optical or optoelectronic,
component comprising a device which comprises a thermoplastic
material which has particles which comprise a core and a shell,
wherein the shell is disposed on the surface of the core and
wherein the core comprises aluminium.
2. The component according to claim 1, wherein the shell is
disposed directly on the surface of the core.
3. The component according to claim 1, wherein the shell comprises
an oxide, a nitride or an oxynitride.
4. The component according to claim 1, wherein the shell has a
thickness of greater than 10 nm.
5. The component according to claim 1, wherein the shell has a
thickness of less than 100 .mu.m.
6. The component according to claim 1, wherein the shell
electrically insulates the core .
7. The component according to claim 1, wherein the shell comprises
a coating on its surface.
8. The component according to claim 1, wherein the particles have
an average particle size, measured as the d50-value, of 10 nm to 50
.mu.m.
9. The component according to claim 1, wherein the concentration of
particles in relation to the thermoplastic material is between
0.001 and 5% by weight.
10. The component according to one claim 1, wherein the core has an
aluminium content of at least 99 mol.%.
11. The component according to claim 1, wherein the core comprises
an aluminium alloy.
12. The component according to claim 1, wherein the device is a
housing.
13. A method for the production of a device for an electronic, in
particular for an optical or optoelectronic, component, comprising
A) providing a thermoplastic material; B) incorporating particles
which comprise a core and a shell, wherein the shell is disposed on
the surface of the core and wherein the core comprises aluminium;
and: C) forming a device.
14. The method according to claim 13, wherein the particles from
method step B) are produced in a preceding method which comprises
the steps of: a) melting aluminium, b) atomising the melt from
method step a), so that cores are formed, c) grinding the cores
from method step b), and d) conditioning the cores from method step
c), so that a shell is formed on the surface of the cores.
15. The method according to claim 14, wherein the particles are
dried prior to method step B) and after method step d) in a method
step e).
16. . An optoelectronic component comprising a device which
comprises a thermoplastic material which has particles which
comprise a core and a shell, wherein the shell is disposed on the
surface of the core and wherein the core comprises aluminium.
17. An electronic, in particular optical or optoelectronic,
component comprising a device which comprises a thermoplastic
material which has particles which comprise a core and a shell,
wherein the shell is disposed on the surface of the core and
wherein the core comprises aluminium, wherein the shell comprises a
coating on its surface, wherein the coating comprises a lubricant,
wherein the type and concentration of the lubricant can be selected
in such a manner that the particles are disposed on the surface of
the device and to a lesser extent in the interior of the device or
the type and concentration of the lubricant can be selected in such
a manner that the particles become enriched primarily in the
interior of the device.
Description
[0001] Electronic, in particular optical or optoelectronic,
component and method for the production thereof
[0002] This patent application claims the priority of German patent
application 10 2009 047 877.9 and German patent application 10 2009
055 765.2, the disclosure content of which is hereby incorporated
by reference.
[0003] An electronic, in particular optical or optoelectronic,
component is provided in accordance with claim 1.
[0004] A very widespread problem of optical or optoelectronic
components is that ever brighter radiation sources having higher
operating temperatures and shorter wavelengths are used, and as a
result the housing can be damaged by e.g. yellowing and chalking
phenomena. As a consequence, e.g. the reflector can be damaged and
therefore important optical properties such as the operating
duration of the component or even the light yield can be
significantly downgraded and the characteristic of the light
emission can be changed.
[0005] An object of embodiments of the invention is to provide an
electronic component which has an improved yellowing behaviour.
[0006] The object is achieved by an electronic component in
accordance with claim 1. Further embodiments are described in
further dependent claims.
[0007] One embodiment of the invention relates to an electronic, in
particular optical or optoelectronic, component comprising a device
which comprises a thermoplastic material which has particles which
comprise a core and a shell, wherein the shell is disposed on the
surface of the core and wherein the core comprises aluminium. The
device can also consist of the thermoplastic material which has the
particles. The core can comprise, or consist of, elemental
aluminium.
[0008] By reason of their thermomechanical properties thermoplastic
materials have good media resistance and adequate temperature and
dimensional stability. They also have good fracture strength and
crack resistance when the devices are subjected to cyclic and
soldering bath loads. By reason of the low costs, it is also
possible to produce large quantities of components in a
cost-effective manner.
[0009] Aluminium particles have the following advantageous
properties: they are non-toxic, available on the market at a
favourable price, corrosion-resistant and media-resistant. They
have a high thermal conductivity of about 220 W/mK. If they have a
shell (e.g. an oxide layer on the surface) then they have at the
same time good electrically insulating properties by reason of this
shell. The good metallic reflectivity and the simultaneously high
absorptivity in a broad wavelength range (UV to IR) render it
possible primarily to use the particles in devices for optical or
optoelectronic components.
[0010] In this application, the invention is described as being
representative of electronic components with particular attention
to optical or optoelectronic components. The embodiments relating
to the optical or optoelectronic components also apply accordingly
to electronic components.
[0011] A device which comprises such a thermoplastic material which
has these particles with a core and shell has improved adhesion to
e.g. metallic leadframes. This prevents the penetration of moisture
or other harmful substances into the boundary surface of the device
and leadframe which is susceptible to stress. By virtue of the
increased barrier effect which is provided by the addition of the
particles in the thermoplastic material, moisture absorption of the
device and the diffusion of harmful gases by the device are also
reduced.
[0012] By reason of the improved thermal conductivity of the
device, the heat losses which occur during operation of the
component can also be discharged more efficiently, whereby the
ageing of the device in the housing material is reduced. As a
consequence, the operating temperature of the component can also be
increased. Furthermore, the component can be processed at higher
temperatures.
[0013] In a further embodiment, the shell is disposed directly on
the surface of the core.
[0014] Therefore, the core which comprises aluminium is surrounded
directly by the shell. In one embodiment, the shell is fixedly
connected to the surface of the core. Preferably, the shell is
inseparably connected to the surface, e.g. if the shell develops or
is produced as a result of a chemical reaction, in particular a
solid state reaction, such as e.g. the formation of an oxide layer.
Therefore, the material, of which the shell consists, is preferably
a solid material.
[0015] In a further embodiment of the invention, the shell
comprises an oxide, a nitride or an oxynitride.
[0016] Shells of these materials have a good electrically
insulating property in combination with good thermal conductivity.
They are also non-toxic and are significantly more
corrosion-resistant and media-resistant compared with a metal.
Preferably, the shell likewise comprises aluminium, e.g. as
AlO.sub.x, AlN.sub.x, AlO.sub.xN.sub.y.
[0017] In a further embodiment of the invention, the shell has a
thickness of greater than 10 nm.
[0018] A shell of this thickness serves to ensure an adequate
electrically insulating property, as well as adequate corrosion
protection for the core of the particles.
[0019] In a further embodiment of the invention, the shell has a
thickness of less than 100 .mu.m.
[0020] A shell thickness below 100 .mu.m already has the
above-described advantageous properties. A thickness of <100
.mu.m renders it possible to minimise the particle size per se,
which inter alia is important for the optical properties of the
device. The thickness of the shell is preferably in a range of 50
nm to 25 .mu.m.
[0021] For the purpose of directed reflection of radiation,
particles having a smooth surface are preferably used, whereas for
the purpose of a diffuse reflection particles having a rough
surface are preferably used.
[0022] In a further embodiment of the invention, the shell
electrically insulates the core.
[0023] This renders it possible to manufacture the core from an
electrically conductive material and still use the particles in a
range where the particles as a whole must be electrically
insulating with respect to the area surrounding them. Therefore,
this also permits the use of the particles in a thermoplastic
material which can be used for a device which is used for an
optoelectronic component. Therefore, the device can also be e.g. a
cast device which is disposed on electrically conductive devices,
which are not insulated towards the outside, of an optoelectronic
component, such as e.g. contact elements. By virtue of the fact
that the particles have electrically insulating properties, the
entire thermoplastic material thus preferably has electrically
insulating properties, thus preventing the risk of a short-circuit
via the housing material which is manufactured from the
thermoplastic material.
[0024] In a further embodiment of the invention, the shell at least
partially comprises a coating on its surface.
[0025] The coating can be e.g. a coating of grinding aids. In one
embodiment, a coating is provided which comprises a grinding aid.
The grinding aid can be e.g. an animal or vegetable lubricant, as
well as organic phosphonic acids or phosphonic acid esters. The
animal and vegetable lubricants can be e.g. palmitic acid, stearic
acid or oleic acid and the salts thereof with Zn, Ca or Mg.
[0026] In this case, the type and concentration of the lubricants
can be selected in such a manner that during introduction of the
particles into the thermoplastic material and during the subsequent
production of the device the particles are disposed on the surface
of the device and to a lesser extent in the interior of the device
and provide the desired reflective properties. In this case, the
concentration of the lubricant can be e.g. in the range of 0.05 pbw
to 3'pbw in relation to the particle, wherein the range of 0.05 pbw
to 1 pbw is preferred (pbw=parts by weight).
[0027] On the other hand, the type and concentration of the
lubricant can be selected in such a manner that the particles
become enriched primarily in the interior of the device and thus
above all provide good thermal conductivity.
[0028] If the particles are introduced into the device primarily to
improve the thermal conductivity, then they preferably have a lower
concentration of grinding additive in the coating. Furthermore,
these particles preferably have a thin shell. During production,
the particles thus become cold-welded at the contact points.
[0029] In a further embodiment of the invention, the particles have
an average particle size, measured as the d.sub.50 -value, of 10 nm
to 50 .mu.m.
[0030] Preferably, the particles have an average particle size,
measured as the d.sub.50-value, between 10 nm and 20 .mu.m. For
example, the reflectivity can be optimised by the size, shape and
roughness of the particles. Equally, the visual impression of the
device can be influenced by the size of the particles. The device
can thus be afforded a metallic visual effect e.g. using large
particles and a high concentration of particles. The average
particle size can be determined in this case by means of dynamic
light scattering.
[0031] In a further embodiment of the invention, the concentration
of particles in relation to the thermoplastic material is 0.001 to
20% by weight, wherein the range of 0.001 to 5% by weight is
preferred.
[0032] The concentration of particles in the thermoplastic material
is preferably between 0.001 to 1% by weight. Owing to the type and
concentration of particles in the thermoplastic material, it is
possible to control the reflectivity of the device which comprises
the thermoplastic material. For example, the surface of the device
can thus be afforded a metallic character.
[0033] In a further embodiment of the invention, the concentration
of particles in relation to the thermoplastic material is 10 to 75%
by weight.
[0034] In this case, the electronic, in particular optical or
optoelectronic, component can be e.g. a component having a cooling
function. This preferably comprises multimodal particles in flake
form. As a consequence, the highest possible filling material
content can be achieved.
[0035] In a further embodiment of the invention, the concentration
of particles in relation to the thermoplastic material is 0.001 to
10% by weight.
[0036] In this case, the optical or optoelectronic component can be
e.g. a component having good reflective properties. This preferably
comprises spherical particles having a smooth surface, if the
reflection is to be directed. In contrast, if the reflection is to
be diffuse, the component preferably comprises particles with an
irregular, rough surface. In both cases, the particles become
enriched on the surface.
[0037] In a further embodiment of the invention, the core has an
aluminium content of at least 99 mol.%.
[0038] In one embodiment, the core has an aluminium content of 100
mol.%, which means that the core consists completely of aluminium
and optionally of small amounts of typical impurities. Aluminium
proves to be non-toxic and is available on the market at a
relatively favourable price. In comparison with other metals,
aluminium also has a low density which means that the particles are
fairly light.
[0039] In a further embodiment of the invention, the particles have
a spherical form, a weakly ellipsoidal form or a form similar to
these forms. In the case of the weakly ellipsoidal form, there is a
radius ratio of .ltoreq.1.5.
[0040] In a further embodiment of the invention, the particles are
in the form of flakes or have a strongly ellipsoidal form. In the
case of the strongly ellipsoidal form, there is a radius ratio of
>1.5.
[0041] In a further embodiment of the invention, the particles are
in the form of fibres.
[0042] In the event that the particles have are in the form of
flakes, fibres or have a strongly ellipsoidal form, the particles
preferably have an average particle size, measured as the
d.sub.50-value, of 0.1 .mu.m to 200 .mu.m. In this case, an average
particle size of 1.0 .mu.m to 50 .mu.m is preferred and the range
of 1.0 .mu.m to 20 .mu.m is particularly preferred.
[0043] In order to achieve the desired optical properties and the
desired thermal conductivity, it is possible to use particles of
one form and also a mixture of particles of different forms. The
same also applies to the size of the particles. In this case, there
can be a monomodal distribution, i.e., the particles are of a
similar size, such as also a multimodal form, i.e., the particles
are significantly different in terms of their size.
[0044] The form of the particles can control e.g. the reflectivity
such that the reflection is directed or diffuse.
[0045] A diffuse reflection can improve the light-mixing of
radiation of a different wavelength e.g. on the housing wall
surfaces.
[0046] In the event that the particles are in the form of flakes,
fibres or have a strongly ellipsoidal form, the concentration of
the particles in relation to the thermoplastic material is
preferably 0.1 to 40% by weight, wherein the range of 0.1 to 30% by
weight is particularly preferred.
[0047] In a further embodiment of the invention, the core
comprises, or consists of, an aluminium alloy.
[0048] The alloy can comprise e.g. Si and/or Mg. Preferably it
comprises Si. Such alloy components stabilise the core of the
particles. The concentration of the alloy component is preferably
in percentage by weight in relation to the aluminium quantity used
in the range of 10 ppm to 0.9% by weight.
[0049] In a further embodiment of the invention, the thermoplastic
material additionally comprises one or several loading materials
selected from: glass fibres, glass fabric, glass powder, white
pigments such as TiO.sub.2, CaCO.sub.3, BaSO.sub.4,
Al.sub.2O.sub.3, SiO.sub.2, ZrO.sub.2, light-converging substances,
dyers, additives such as wetting agents, stabilisers, inorganic and
metallic nanoparticles such as ZnO, ZrO.sub.2, Au, Ag, Ti,
phosphor-organic flame retardants.
[0050] In a further embodiment of the invention, the thermoplastic
material is a synthetic material selected from polyaryl ether,
polyphenyl ether, polysulfones, polyaryleneethersulfones,
polyaryletherketones, polyetherimides, polycarbonates, polyamide,
fluorine-containing polymers such as polytetrafluorethylene,
tetrafluoroethylene-perfluoropropylene copolymers, polyvinylidene
fluoride, polyvinyl fluoride, LCP and mixtures of different
thermoplastic materials. In this case, the polyphthalamides are
preferred amongst the polyamides.
[0051] In this case, the polyamide can be additionally charged with
glass fibres, glass fabrics, carbon blacks or white pigments.
[0052] In a further embodiment of the invention, the device is a
housing.
[0053] This housing can be formed e.g. as a reflector. The housing
can have a radiation source e.g. in its interior.
[0054] The electronic, in particular optical or optoelectronic,
component can be used e.g. in any one of the following fields:
automotive industry, cooling media with optical functions, light
construction housings and frame material in photovoltaic
installations, medicine or sanitation. The component can be e.g. a
headlight, a light module, a signal installation or a large-area
light design element or an element thereof. This type of usage is
of interest particularly by reason of the low weight and the
heat-dissipating properties of the thermoplastic material which
comprises the particles.
[0055] The electronic, in particular optical or optoelectronic,
component can also be used with an increased level of reliability
for modules and systems, and can be used under more stringent
operating conditions, or it can be used for new applications which
have a broadened functional range, such as e.g. housings for
SMD-capable LEDs.
[0056] The present invention also relates to the use of an
above-described thermoplastic material for the production of a
device for an electronic, in particular for an optical or
optoelectronic, component.
[0057] The thermoplastic material described which comprises the
particles can be used e.g. for housings and/or reflectors in
headlights, light modules, signal installations and a large-area
light design element. The low weight and the heat-dissipating
effect of the thermoplastic material or of the device which
comprises the thermoplastic material can be advantageous. For the
same reason, the described thermoplastic material which comprises
the particles is suitable as a frame material in photovoltaic
applications.
[0058] The thermoplastic material described which comprises the
particles can be used as a thermoplastically processable composite
material. In so doing, design freedom is acquired, which means that
it can be used e.g. for cost-effective cooling channels in
electronic components, modules and systems.
[0059] In addition to the component itself, the present invention
also relates to a method for the production of a device for an
electronic, in particular for an optical or optoelectronic,
component.
[0060] In one variant of the method for the production of a device
for an electronic, in particular for an optical or optoelectronic,
component the method includes the method steps of: providing a
thermoplastic material as method step A), incorporating particles
which comprise, or consist of, a core and a shell, wherein the
shell is disposed on the surface of the core and wherein the core
comprises aluminium, as method step B) and forming a device as
method step C).
[0061] In this case, the advantages explained with regard to the
component also apply in a analogous manner to the method.
[0062] In a further variant of the method, the particles from
method step B) are produced in a preceding method which comprises
the steps of:
melting aluminium as method step a), atomising the melt from method
step a), so that cores are formed, as method step b).
[0063] In a further variant, this preceding method additionally
comprises the step of:
grinding the cores from, method step b), as method step c).
[0064] In a further variant, this preceding method additionally
comprises the step of: conditioning the cores, so that a shell is
formed on the surface of the cores, as method step d). In this
case, method step d) can be performed prior to or after method step
c).
[0065] In this case, the shell can also be formed between the core
and a coating disposed thereon. In this case, the coating can be
partially removed by the conditioning.
[0066] An exemplified embodiment will be described in greater
detail hereinafter. The aluminium which is e.g. highly pure
aluminium having a content of >99 mol.% is melted at a
temperature of ca. 700.degree. C. in method step a). In subsequent
method step b), the molten aluminium is atomised at high pressure
with air or inert gas (nitrogen, Ar, He). The atomising system and
the atomising parameters have an influence upon the size and form
of the cores. This can even have an indirect influence upon e.g.
the thickness of the subsequent shell. The cores are ground in
subsequent method step c). The grinding can be e.g. wet grinding in
hydrocarbons, solvent naphtha, petroleum ether or toluene. This can
be performed e.g. at a temperature of up to 70.degree. C. The
grinding can be performed e.g. using spherical grinding bodies of a
defined size and quantity. During the grinding step, grinding aids
such as e.g. waxes, oleic acid, stearic acid or palmitic acid can
be added. In this case, the particle form depends to a very
significant extent upon the grinding energy introduced and the
hardness of the grinding bodies.
[0067] In a further variant, the grinding aids are completely or
partially removed with organic solvents by washing.
[0068] In a further variant, the particle size and particle
distribution are optimised by screening processes.
[0069] The conditioning of the cores in method step d) can be
performed e.g. in a furnace at a temperature of 400.degree. C. The
conditioning can be performed over a period of e.g. 1 to 12 hours.
The atmosphere used in this case can be e.g. air, oxygen, nitrogen
or argon. Further surface modifications such as e.g. passivations
can also be performed in plasma (oxygen, air, argon and mixtures
thereof). In this case, the plasma power and the duration of the
plasma treatment can be adjusted accordingly to the desired
objectives. The particles which are thus obtained are stable with
respect to moisture and are also hydrolysis-stable over the entire
pH value range.
[0070] In a further variant of the method, the particles are dried
prior to method step B) and after method step d) in a method step
e). Drying can be effected e.g. over a period of 1 to 2 hours at a
temperature of 120.degree. C. In this case, a vacuum (<13 mbar)
can also be applied at the same time.
[0071] In a further variant of the method, the processing of the
thermoplastic material comprises the method steps of: preparing,
drying, homogenising the raw materials and shaping. Each of the
steps can be performed independently of each other in an atmosphere
which comprises air or inert gas. In this case, the inert gas
atmosphere can comprise nitrogen, argon or helium and is e.g.
expedient if the formation of a shell, which comprises ALO.sub.x is
not desired in this method step.
[0072] The method can comprise additional wet-chemical or
dry-chemical-physical processes.
[0073] The above-described thermoplastic material can be used e.g.
for cooling purposes in optical or optoelectronic components. For
instance, the thermoplastic material can be used e.g. for
SMD-components which can be used e.g. in the automotive
industry.
[0074] The above-described thermoplastic material can also be used
for minimising corrosion in e.g. leadframes. They can be e.g.
leadframes which are silver-coated. They can be cast e.g. with
silicone or silicone hybrids. Thermoplastic materials which
comprise particles which have a shell of <5 .mu.m, preferably
<1 .mu.m, are particularly suitable for this purpose. They can
act as sources of aluminium which can emit Al.sup.3+ ions.
[0075] Variants of the invention will be described in detail
hereinafter with reference to Figures and exemplified
embodiments.
[0076] FIGS. 1a and 1b each show a schematic cross-section of one
embodiment of a particle.
[0077] FIGS. 2a and 2b each show a schematic cross-section of an
embodiment of an optoelectronic component.
[0078] FIG. 1a shows a schematic cross-section of a particle 1. The
particle consists of a core 2 and a shell 3 which is disposed
directly on the surface of the core 2.
[0079] FIG. 1b shows a schematic cross-section of a further
embodiment of the particle 1. In comparison with the particle
illustrated in FIG. 1a, this particle additionally comprises a
coating 4 which is disposed directly on the surface of the shell
3.
[0080] FIG. 2a shows a schematic cross-section of one embodiment of
an optoelectronic component. This component comprises a device 6
which is manufactured from a thermoplastic material 5. The
thermoplastic material 5 comprises particles 1. In this exemplified
embodiment, the device 6 is formed as a reflector. Disposed in the
interior of the reflector trough is a radiation source 7. The
radiation source 7 can be e.g. an inorganic LED or an organic LED
(OLED). The radiation source 7 is cast with a casting compound 8
which forms a lens 9 on the radiation exit surface. The radiation
emitted by the radiation source 7 can be reflected by the
reflector, thus increasing the light yield of the optoelectronic
component. The heat which develops during operation of the
radiation source can be dissipated to the surrounding area via the
device 6. In this case, the thermal conductivity is significantly
increased by the particles 1 which are introduced into the
thermoplastic material 5. This embodiment is e.g. very suitable for
cooling the device. The particles preferably have a large surface,
as is the case in flake form.
[0081] The LED comprises a semiconductor which forms a diode. LEDs
are often so-called III/V-semiconductors, i.e., they are
constructed from elements of the 3rd and 5th group of the periodic
table. Furthermore, the LED comprises an anode which is located
e.g. on the upper side of the LED, and a cathode which can be
disposed accordingly on the underside. The anode can be connected
in an electrically conductive manner via a bond wire to the
leadframe, on which the LED can be disposed. If a voltage is
applied in the forward direction, electrons migrate to the
recombination layer at the p-n transition. On the n-doped side, the
electrons populate the conduction band in order to change to the
p-doped valency band, which in energy terms is more favourable,
once the boundary surface has been passed. At this location, the
electrodes then recombine with the holes present in this case.
[0082] An OLED comprises a layer stack comprising an anode and a
cathode, from which by the application of a voltage holes or
electrodes are emitted which travel in the direction of the
respective other electrode. The charge carriers travel in this case
e.g. initially through hole- or electron-transporting layers,
before they impinge upon one another in a light-emitting layer. In
this layer, the electrons together with the holes form excitons.
The excitons can excite luminescent substances which are located in
the emitting layer, for the emission of radiation. The OLED can
comprise an organic functional layer which can be e.g. a
light-emitting, charge carrier-blocking or charge
carrier-transporting layer or a combination thereof.
[0083] FIG. 2b shows a schematic cross-section of a further
embodiment of an optoelectronic component. This component, just
like the embodiment illustrated in FIG. 2a, comprises a device 6
which is manufactured from a thermoplastic material 5. The
thermoplastic material 5 comprises particles 1. In this case, the
device 6 is also formed as a reflector. Disposed in the interior of
the reflector trough is a radiation source 7. The radiation source
7 can likewise be e.g. an -inorganic LED or an organic LED (OLED).
The radiation source 7 is cast with a casting compound 8 which
forms a lens 9 on the radiation exit side. In contrast to the
embodiment which is illustrated in FIG. 2a, the particles 1 in this
embodiment are disposed on the surface of the device 6. The surface
thus has a particularly high reflectivity. The thermoplastic
material comprises preferably spherical particles having a smooth
surface, if the reflection is to be directed. In contrast, if the
reflection is to be diffuse, the thermoplastic material preferably
has particles having an irregular rough surface.
[0084] The invention is not limited by the description using the
exemplified embodiments. On the contrary, the invention includes
any new feature and any combination of features included in
particular any combination of features in the claims, even if this
feature or this combination itself is not explicitly stated in the
claims or exemplified embodiments.
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